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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* istream.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "../internal.h"
typedef struct {
istream_t base;
char *path;
int fd;
bool eof;
size_t buffer_offset;
size_t buffer_used;
sqfs_u8 buffer[BUFSZ];
} file_istream_t;
static int precache(istream_t *strm)
{
file_istream_t *file = (file_istream_t *)strm;
if (file->eof)
return 0;
if (file->buffer_offset > 0 &&
file->buffer_offset < file->buffer_used) {
memmove(file->buffer, file->buffer + file->buffer_offset,
file->buffer_used - file->buffer_offset);
}
file->buffer_used -= file->buffer_offset;
file->buffer_offset = 0;
while (file->buffer_used < BUFSZ) {
ssize_t ret = read(file->fd, file->buffer + file->buffer_used,
BUFSZ - file->buffer_used);
if (ret == 0) {
file->eof = true;
break;
}
if (ret < 0) {
if (errno == EINTR)
continue;
perror(file->path);
return -1;
}
file->buffer_used += ret;
}
return 0;
}
static int file_get_buffered_data(istream_t *strm, const sqfs_u8 **out,
size_t *size, size_t want)
{
file_istream_t *file = (file_istream_t *)strm;
if (want > BUFSZ)
want = BUFSZ;
if (file->buffer_used == 0 ||
(file->buffer_used - file->buffer_offset) < want) {
int ret = precache(strm);
if (ret)
return ret;
}
*out = file->buffer + file->buffer_offset;
*size = file->buffer_used - file->buffer_offset;
return (file->eof && *size == 0) ? 1 : 0;
}
static void file_advance_buffer(istream_t *strm, size_t count)
{
file_istream_t *file = (file_istream_t *)strm;
assert(count <= file->buffer_used);
file->buffer_offset += count;
assert(file->buffer_offset <= file->buffer_used);
}
static const char *file_get_filename(istream_t *strm)
{
file_istream_t *file = (file_istream_t *)strm;
return file->path;
}
static void file_destroy(sqfs_object_t *obj)
{
file_istream_t *file = (file_istream_t *)obj;
if (file->fd != STDIN_FILENO)
close(file->fd);
free(file->path);
free(file);
}
istream_t *istream_open_handle(const char *path, int fd)
{
file_istream_t *file = calloc(1, sizeof(*file));
istream_t *strm = (istream_t *)file;
if (file == NULL) {
perror(path);
return NULL;
}
sqfs_object_init(file, file_destroy, NULL);
file->path = strdup(path);
if (file->path == NULL) {
perror(path);
goto fail_free;
}
file->fd = dup(fd);
if (file->fd < 0) {
perror(path);
goto fail_path;
}
close(fd);
strm->get_buffered_data = file_get_buffered_data;
strm->advance_buffer = file_advance_buffer;
strm->get_filename = file_get_filename;
return strm;
fail_path:
free(file->path);
fail_free:
free(file);
return NULL;
}
istream_t *istream_open_file(const char *path)
{
istream_t *out;
int fd;
fd = open(path, O_RDONLY);
if (fd < 0) {
perror(path);
return NULL;
}
out = istream_open_handle(path, fd);
if (out == NULL)
close(fd);
return out;
}
istream_t *istream_open_stdin(void)
{
return istream_open_handle("stdin", STDIN_FILENO);
}
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